1. Field of the Invention
The present invention relates to a keypad, and more particularly to a keypad having an illumination means and a method for fabricating same.
2. Description of the Related Art
Generally, mobile terminals have an illumination means which emits light to enable the users to use a keypad in the dark. The illumination means can have a structure that disposes a plurality of light emitting diodes on a PCB (Printed Circuit Board) or a structure that inserts an inorganic electro-luminescence element into an elastic pad.
FIG. 1 is a view illustrating a conventional keypad assembly 100 with a plurality of light emitting diodes. The keypad assembly 100 includes a switch board 150, a plurality of light emitting diodes (LEDs) 170 and a keypad 110.
The keypad 110 includes a plate-shaped elastic layer 120 which is made from a rubber material, a plurality of key tops 140 disposed on a first surface 122 of the elastic pad 120 and imprinted with numbers and characters, and a plurality of protrusions 130 projected downwardly from a second surface 124 of the elastic pad 120. The protrusions 130 are centrally disposed below the corresponding key tops 140. Also, the elastic pad 120 has a plurality of grooves 126 on the second surface 124 thereof so that the plurality of LEDs 170 can be inserted into the grooves 126.
The switch board 150 includes a switch sheet placed on top of a printed circuit board (PCB) 155. The switch sheet has a plurality of switches 160 on the top thereof. Each switch 160 consists of a conductive contact member 162 and a conductive dome 164 that completely covers the contact member 162. In addition, the LEDs 170 are mounted on the switch sheet.
In the prior art, a keypad assembly having a keypad with an inorganic electro-luminescence element inserted into an elastic layer has also been suggested. However, a separate AC power is needed to use the inorganic electro-luminescence element. In other words, conventional keypad assemblies including inorganic electro-luminescence element further include a separate inverter for converting a DC (direct current) voltage into an AC (alternating current) voltage, which increases the size and manufacturing cost of the keypad assembly and complicates the keypad assembly fabricating process.